Cahoon was born in
Providence in the
Colony of Rhode Island and Providence Plantations to Daniel Cahoon Jr (1737-1811) and Lillis (Dyer) Cahoon (1740-1832). He attended the
common schools. He moved with his parents to
Lyndon, Vermont, in 1791 and engaged in milling and agricultural pursuits.
Political career He was a member of the Vermont State House of Representatives from 1802 until 1810. He succeeded his father as town clerk in Lyndon, and served from 1808 until 1829. Cahoon was a
presidential elector in 1808 and voted for Madison and Langdon.
Congress He was elected an Anti-Masonic candidate to the
Twenty-first United States Congress and the
Twenty-second United States Congress, serving from March 4, 1829, until March 3, 1833.{{cite web|url= http://www.govtrack.us/congress/members/william_cahoon/402181 He was an unsuccessful candidate in 1832 for reelection to Congress. ==Personal life==